1998 Buick Riviera Owner's Manual

As shown in the chart, SAE IOW-30 is best for yourvehicle. However, you can use SAE 5W-30 if it’s goingto be colder than 60°F (16” C) before your next oilchange. When it’s very cold, you should use SAE5W-30. These numbers on an oil container show itsviscosity, or thickness. Do not use other viscosity oils,such as SAE 20W-50.NOTICE:Use only engine oil with the American PetroleumInstitute Certified For Gasoline Engines“Starburst” symbol. Failure to use therecommended oil can result in engine damage notcovered by your warranty.GM Goodwrench@ oil meets all the requirements foryour vehicle.If you are in an area where the temperature falls below-20°F (-29”C), consider using either an SAE 5W-30synthetic oil or an SAE OW-30 oil. Both will provideeasier cold starting and better protection for your engineat extremely low temperatures.Engine Oil AdditivesDon’t add anything to your oil. Your dealer is ready toadvise if you think something should be added.When to Change Engine OilIf any one of these is true for you, use the short tripkitymaintenance schedule:Most trips are less than 5 to 10 miles (8 to 16 km).This is particularly important when outsidetemperatures are below freezing.Most trips include extensive idling (such as frequentdriving in stop-and-go traffic).Most trips are through dusty areas.You frequently tow a trailer or use a carrier on topof your vehicle.The vehicle is used for delivery service, police, taxior other commercial application.Driving under these conditions causes engine oil tobreak down sooner. If any one of these is true for yourvehicle, then you need to change your oil and filterevery 3,000 miles (5000 km) or 3 months -- whicheveroccurs first.